Air conditioner condensation pan overflow protection

ABSTRACT

A liquid level sensor ( 100 ) is added to air conditioner condensation pan(s) ( 40  and/or  50 ) to prevent overflow and subsequent house damage by turning off the compressor ( 80 ) and the fan ( 20 ) by means of a circuit breaker ( 120 ) and associated electronics ( 110 ).

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is entitled to the benefit of Provisional Patent Application Ser. #60/214443, 2000 Jun. 28.

BACKGROUND—FIELD OF INVENTION

[0002] This invention relates to refrigeration air conditioner condensation pans, specifically to a method of preventing the overflow of such pans and the subsequent damage caused by such overflow.

BACKGROUND—DESCRIPTION OF PRIOR ART

[0003] Refrigeration air conditioners for homes usually have the cooling coils mounted in the attic. During the cooling process, water is condensed from the air, is caught in one or more condensation pans mounted below the cooling coils, and must be removed by drains in the pan or pans. These drains often plug up, and the water in the pans overflows and causes structural and property damage to the house. This is a common occurrence. It has happened to us twice, and to many of our friends and neighbors.

SUMMARY

[0004] In accordance with the present invention, a liquid level sensor and associated electronics are attached to an air conditioner condensation pan or pans, to prevent overflow by shutting off the air conditioner fan and compressor, and optionally sounding an alarm.

OBJECTS AND ADVANTAGES

[0005] Accordingly, several objects and advantages of my invention are:

[0006] (a) to prevent the air conditioner condensation pan overflow and subsequent damage to houseand property by shutting off the fan and compressor;

[0007] (b) to prevent the air conditioner from being restarted until the pan drain(s) is/are cleared of obstruction and the pan(s) drain properly.

DRAWING FIGURES

[0008]FIG. 1 is a schematic drawing of the condensation pan(s) associated with the cooling coils of a refrigeration air conditioner, and the drains to such pans.

[0009]FIG. 2 is a schematic of the electrical wiring associated with the refrigeration air conditioner.

[0010]FIG. 3 shows an installation of a liquid level sensor in one condensation pan of a refrigeration air conditioner.

[0011]FIG. 4 shows one embodiment of the electronic circuitry required to shut off the air conditioner fan and compressor.

[0012]FIG. 5 shows an alternative embodiment of the electronic circuitry, incorporating an alarm circuit.

REFERENCE NUMERALS IN DRAWINGS

[0013]10 cooling coils

[0014]15 refrigerant lines

[0015]20 fan

[0016]25 electrical lines from thermostat to fan

[0017]30 ductwork

[0018]40 primary condensation pan

[0019]45 primary condensation pan drain

[0020]50 secondary condensation pan

[0021]55 secondary condensation pan drain

[0022]60 electrical lines from thermostat, fan, compressor

[0023]70 thermostat

[0024]80 compressor

[0025]90 electrical lines from thermostat to compressor

[0026]95 alternative condensation pan drain

[0027]100 liquid level sensor

[0028]105 wiring from liquid level sensor to sensor power supply and trigger

[0029]110 sensor power supply and trigger

[0030]120 circuit breaker

[0031]130 alarm

DESCRIPTION—FIGS. 1, 2 and 3—PREFERRED EMBODIMENT

[0032] A standard home refrigeration attic installation is shown in FIG. 1. A compressor sends refrigeration fluid through refrigerant lines 15 to a set of cooling coils 10 mounted in ductwork 30 in an attic. The cooling coils have moist air blown across them by a fan 20 controlled by a thermostat 70 through wiring 25, and into the ductwork 30. The condensed moisture from the air falls into one or more condensation pans 40, 50 and is drained into the house sewer or out of the house at the roofline through drains 45, 55. In some home installations, only one pan 40, called the primary pan, is used, while other installations use two pans 40, 50, a primary and a secondary pan. The secondary pan is below the primary pan, and larger, in order to catch any spillage from the primary pan.

[0033]FIG. 2 shows the standard electrical wiring associated with a refrigeration air conditioner. A thermostat 70 in the house senses the air temperature, and turns the compressor 80 and the fan 20 on or off as required. Power for the thermostat, fan and compressor is furnished from the house power lines 60. The thermostat 70 switches the compressor 80 and the fan 20 on and off through different circuits 90, 25.

[0034] A preferred embodiment of the present invention is shown in FIG. 3. A liquid level sensor 100 is attached to the inside of each existing condensation pan 45, 55. The liquid level sensor has its associated electronics 110 consisting of a power supply and a triggering mechanism connected to a circuit breaker 120 in the main leg of the power line leading to the compressor 80 and the fan 20. The circuit breaker 120 remains closed until the liquid level sensor 100 senses that water is about to spill from one or both pans. At that point, the triggering electronics 110 will open the circuit breaker 120, preventing power from getting to the compressor 80 and the fan 20. The circuit breaker 120 will remain open until the condensation pan drain(s) is/are cleared, the water level returns to a normal state, and the circuit breaker is reset manually. Any attempt to reset the circuit breaker while the pans are still close to spilling will cause the circuit breaker to open again. Such a circuit is shown in FIG. 4.

[0035] In the preferred embodiment, the liquid level sensor can be an optoSchmitt sensor such as the LL series manufactured by Honeywell. However, the sensor and its associated electronics can be any type of liquid level sensor such as those described in various engineering manuals. Many types of physical effects can be used to determine liquid level: pressure, mechanical, conductive, capacitive, photoelectric, heat-sensing, ultrasonic, nuclear, microwave, and damped-oscillation effects have all been used as liquid-level sensors. A good reference is “Handbook of Transducers,” by Harry N. Norton, Prentice-Hall, Englewood Cliffs, N.J., 1989.

ADDITIONAL EMBODIMENT

[0036] An addition of an alarm 140 to the liquid level sensor circuit can alert the homeowner or a neighbor to a potentially damaging situation. Such a circuit is shown in FIG. 5.

ADDITIONAL EMBODIMENT

[0037] An addition of a liquid level sensor, associated electronics, a circuit breaker and an alarm to “swamp” or evaporative air conditioner drain pans can prevent overflow and roof and home interior damage, since evaporative units are generally roof-mounted.

OPERATION OF INVENTION

[0038] A home refrigeration air conditioning unit works by compressing a refrigerant with a compressor 80 through cooling coils 10 mounted in ductwork 30. A fan 20 circulates household air across the cooling coils 10 through and out of the ductwork 30, into the interior of the house, and back into the ductwork 30.

[0039] The cooling coils 10, fan 20 and ductwork 30 are usually mounted in the attic of a house.

[0040] When the air is cooled by passing across the cooling coils 10, water condenses out of the air and falls into one or more condensation pans 40, 50. This water is drained to the house sewer plumbing, or to the outside of the house, via drains 45, 55 in the pans.

[0041] Some installations of refrigeration units have only one condensation pan, called the primary pan 40. Other installations have two pans, called the primary pan 40 and the secondary pan 50. The secondary pan 50 catches and drains any water spilling from the primary pan 40 due to malfunction of the primary pan drain 45.

[0042] In some installations of the refrigeration units, the primary pan 40 is an integral part of the fan-cooling coil-ductwork assembly 10, 20, 30.

[0043] Some installations of the condensation pans have the drains 45, 55 on the pan sides, and some installations have the drains 45, 55 on the pan bottoms.

[0044] If both the primary pan drain 45 and secondary pan drain 55 are stopped up, or otherwise unable to conduct water away at a sufficient rate from the pans, the pans will overflow into the attic, causing structural and property damage to the house. In hot, humid climates such as the Texas Gulf Coast, refrigeration units can condense as much as 6 gallons of water a day from the air during normal operation.

[0045] The present invention proposes adding a liquid level sensor 100 to each existing condensation pan 40, 50, to prevent water overflow. The sensor 100 will determine when the liquid level in the pans 40, 50 is about to overflow the edge of the pans, and will shut off the electricity to the fan 20 and the compressor 80 through its power supply electronics and trigger circuit 110.

[0046] The electricity is shut off by a circuit breaker 120 in one leg of the power lines to the compressor 80 and fan 20. This circuit breaker is opened by the action of the trigger circuit 110 of the liquid level sensor. The compressor 80 and fan 20 cannot be restarted before the circuit breaker 120 is manually re-engaged. Since the liquid level sensor circuitry 110 is always attached to the power lines, any attempt to reset the circuit breaker 120 before the pans 40, 50 are drained will result in the circuit breaker 120 being opened again.

[0047] An addition of an alarm 130 to the liquid level sensor 100 and its electronics 110 will alert the homeowner, or neighbors or friends if the occupants of the house are not at home.

ADVANTAGES

[0048] From the description above, three advantages of my invention become apparent:

[0049] (a) the liquid level sensor and its circuitry shut off the compressor and fan, thus eliminating condensed water overflow from the condensation pans and subsequent damage to the home and its contents.

[0050] (b) the compressor and fan cannot be started again until the pan drain blockage(s) is/are cleared and the liquid level goes down below the sensor level.

[0051] {circle over (c)} installation of such a protective system to the drain pan of an evaporative air conditioner will also prevent overflow and subsequent damage. 

1. A method for preventing the overflow of refrigeration air conditioner condensation pan(s), comprising: a) a liquid level sensor in the pan or pans, and b) sensor electronic circuitry to activate the sensor, and c) a connection between the sensor circuitry and circuit breakers in the air conditioner compressor and fan power lines, and d) a connection between the sensor circuitry and an alarm, whereby a rise in the level of condensed water in the pan or pans to a point near spillage will turn off the compressor and fan, and activate an alarm.
 2. The liquid level sensor and associated circuitry of claim 1, used to prevent the overflow of the drain pan on evaporative air conditioners by shutting off the water pump and activating an alarm. 